High resolution electron beam lithography of PMGI using solvent developers

Cui, Bo; Veres, Teodor

doi:10.1016/j.mee.2008.01.008

Cited by 18 publications

(13 citation statements)

References 8 publications

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“…Since there is no hard etching mask (Cr) on the ridge during the RIE of pillars, the ridges would shrink for order 10 nm depending on the etched depth. As both PMGI (using solvent developers) and ZEP-520A are high-resolution resists with high contrasts [8,9], smaller features could be fabricated using the current process.…”

Section: Process For Nanoimprint Mold Fabrication and Resultsmentioning

confidence: 99%

“…As the dissolution rate by a base solution increases drastically when PMGI is exposed to electrons, it is effectively an EBL resist with sensitivity of 50–100 μC/cm 2 [6,7]. However, its sensitivity drops considerably to ~1,000 μC/cm 2 when using solvent developers such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK) [8], making it a suitable choice for the current bi-layer resist process. The rather low sensitivity of PMGI does not increase the e-beam writing time significantly because the exposure area of the pillars is much less than that of the trenches.…”

Section: Bi-layer Ebl Resistmentioning

confidence: 99%

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Mold Fabrication for 3D Dual Damascene Imprinting

Rahman

Cui

2010

Nanoscale Res Lett

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Previously, a damascene process based on nanoimprint lithography has been proposed (Schmid G M, et al. in J Vac Sci Technol B 24(3) 1283, 2006) to greatly reduce the fabrication steps of metal interconnection in integrated circuit. For such a process to become a viable technique, a mold having two pattern levels with precise alignment between them must be fabricated first. To this end, this work demonstrates a “self-aligned” fabrication process where the two pattern levels would be perfectly aligned if ignoring the noise during e-beam writing. The process is based on one EBL on a bi-layer resist stack, with the sensitivity for the top layer much higher than that of the bottom layer, which enables separate pattern transfer of the two pattern levels. Using ZEP-520A and poly(dimethylglutarimide) (PMGI) resists, we fabricated pillars having a diameter of 150 nm sitting on ridges having a width of 1.5 μm, which can be used to create via-holes and trenches for IC interconnect by nanoimprint lithography. The current process can also find applications in other areas that require two-level patterning with precise alignment between them.

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Section: Process For Nanoimprint Mold Fabrication and Resultsmentioning

confidence: 99%

Section: Bi-layer Ebl Resistmentioning

confidence: 99%

Mold Fabrication for 3D Dual Damascene Imprinting

Rahman

Cui

2010

Nanoscale Res Lett

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“…Recently, it was discovered that PMGI has a contrast close to that of PMMA, yet approximately four times less sensitive, when developed with common PMMA developers. 9 However, we have shown that using a weak solvent, xylenes, which is a common developer for ZEP, the contrast of PMGI can be higher than 12. This high contrast enables the formation of narrow trenches in a thick layer of the resist; sub 20 nm features with aspect ratios of approximately 30:1 are readily achievable as shown in Fig.…”

Section: Introductionmentioning

confidence: 91%

High aspect ratio features in poly(methylglutarimide) using electron beam lithography and solvent developers

Karbasian

Fay

Xing

et al. 2012

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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The properties of poly(methylglutarimide) (PMGI) when used as an electron beam resist are investigated. The results show that PMGI, when developed with a weak developer, xylenes, shows contrast higher than 12, which is comparable to the contrast achieved in cold developed poly(methylmethacrylate), and approximately twice as high as the recently achieved PMGI contrast using other developers. Using this high contrast polymer, sub 20 nm features with aspect ratios greater than 30:1 can be readily achieved. In addition to the superior positive tone behavior, this polymer behaves as a negative tone resist at higher exposure doses. Negative resist features as small as 20 nm can be fabricated when methyl isobutyl ketone is used to develop negative tone PMGI.

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“…Similarly, ZEP resist has ARs limited to 4:1 at 20 keV [6] and to 7:1 at 100 keV [7], albeit with over three times higher sensitivity than PMMA. Another positive-tone resist, polymethylglutarimide (PMGI), has been patterned with an AR of over 2:1 at 30 keV [8] and extremely high AR of 38:1 at 100 keV [9] using an optimized development process. However, the sensitivity of PMGI is four to nine times lower than that of PMMA, requiring up to 18,000 μC/cm 2 [9] to expose a single line.…”

Section: Introductionmentioning

confidence: 99%

“…This represents a greater than two times improvement over benchmark PMMA resist; however, its sensitivity and resolution are lower than those of PMMA using supplier-recommended conditions. Similar to other positive-tone resists such as PMMA [18], PMGI [8], and ZEP [19], SML may be developed in methyl isobutyl ketone (MIBK)/isopropyl alcohol (IPA) (1:3) solution and rinsed in IPA [20]. …”

Section: Introductionmentioning

confidence: 99%

SML resist processing for high-aspect-ratio and high-sensitivity electron beam lithography

2013

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A detailed process characterization of SML electron beam resist for high-aspect-ratio nanopatterning at high sensitivity is presented. SML contrast curves were generated for methyl isobutyl ketone (MIBK), MIBK/isopropyl alcohol (IPA) (1:3), IPA/water (7:3), n-amyl acetate, xylene, and xylene/methanol (3:1) developers. Using IPA/water developer, the sensitivity of SML was improved considerably and found to be comparable to benchmark polymethylmethacrylate (PMMA) resist without affecting the aspect ratio performance. Employing 30-keV exposures and ultrasonic IPA/water development, an aspect ratio of 9:1 in 50-nm half-pitch dense grating patterns was achieved representing a greater than two times improvement over PMMA. Through demonstration of 25-nm lift-off features, the pattern transfer performance of SML is also addressed.

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High resolution electron beam lithography of PMGI using solvent developers

Cited by 18 publications

References 8 publications

Mold Fabrication for 3D Dual Damascene Imprinting

Mold Fabrication for 3D Dual Damascene Imprinting

High aspect ratio features in poly(methylglutarimide) using electron beam lithography and solvent developers

SML resist processing for high-aspect-ratio and high-sensitivity electron beam lithography

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